Changes in Glial Fibrillary Acidic Protein Immunoreactivity in the Dentate Gyrus and Hippocampus Proper of Adult and Aged Dogs

Abstract

Astrocytes perform neuron-supportive tasks, repair and scarring process in the central nervous system. In this study, we observed glial fibrillary acidic protein (GFAP), a marker for astrocytes, immunoreactivity in the dentate gyrus and hippocampus proper (CA1–3 region) of adult (2–3 years of age) and aged (10–12 years of age) dogs. In the adult group, GFAP immunoreactive astrocytes were distributed in all layers of the dentate gyrus and CA1–3 region, except in the stratum pyramidale of the CA1–3 region. In the aged group, GFAP immunoreactivity decreased markedly in the molecular layer of the dentate gyrus. However, GFAP immunoreactivity in the CA1–3 region increased in all layers, and the cytoplasm of GFAP immunoreactive astrocytes was hypertrophied. GFAP protein levels in the aged dentate gyrus decreased; however, GFAP levels in the CA1–3 region increased. These results suggest that the morphology of astrocytes and GFAP protein levels in the hippocampal dentate gyrus and CA1 region are changed, respectively, with age.